A self-contained, easily installed treadmill is proposed for use by orthopedists and rehabilitation specialists for evaluation and therapeutic interaction of patients with gait problems. This system will continuously monitor the ground reactions of a subject walking in place and display selected gait parameters on a video monitor in real time to permit gait correction via direct biofeedback. The system consists of a treadmill with separate tracks for each limb, a force sensor system to measure the normal, shear, and moment load on each track, and a gait evaluation software package to analyze and provide visual feedback. The technical challenges are to develop: 1) treadmill tracks with sufficiently high frequency response to accurately transmit gait transient loads to the force sensor system, and 2) a highly accurate, low-cost force sensor system. A single treadmill track will be designed, built, and tested to demonstrate its ability to exceed 100 Hz frequency response in normal, shear, and moment load modes, while meeting all structural requirements. A force sensor system will be designed, integrated with the track, and tested to demonstrate its accuracy and repeatability for the three load modes. Output from the sensor system will be integrated with the gait evaluation software. PROPOSED COMMERCIAL APPLICATION: The long-term goal is to make a commercial system available to orthopedists, therapists, and medical practitioners. The treadmill will be designed for office use and suitable for both evaluation and therapy. Future systems enhancements involve integration of joint location sensors into the treadmill package to extend its evaluation and research capabilities to neural-muscle interaction and real-time calculation of resultant joint forces. The elderly, stroke patients, and amputee patients are all groups in need of rehabilitation that would benefit from a widely marketed, economically available device such as that proposed herein.